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Camera without lens

Camera without lens

They develop a camera without a lens from a work of metamaterials

Research into a lensless imaging system could lead to cheap sensors to help avoid car collisions.

US scientists have used metamaterials to build the imaging system, which samples infrared and microwave light.

Metamaterials are materials whose properties are designed for a purpose, rather than being determined by their chemical composition.

The sensor also compresses the images it captures, unlike current compression systems, which only compress images after they have been taken.

Most imaging systems, such as those found in digital cameras, use a lens to focus a scene onto a sensor packed with millions of tiny sensors. A larger number of sensors means that more details are captured and generally produces a higher resolution image.

The imaging system developed by graduate student John Hunt and his colleagues at Duke University in North Carolina does not have a lens and instead combines an aperture or mask of metamaterials and complex mathematics to generate an image of a scene.

Aperture is used to focus, onto a detector, different wavelengths of light present in different parts of a scene. The different frequencies captured in the scene are sampled sequentially.

This sampling helped work out the distribution and mixing of the wavelengths of light captured in a scene, and their relative intensities, Hunt said.

"Then we used some very fancy math developed in computational imaging to turn that data into a 2D image," he added.

The sampling of the wavelengths is carried out electronically, so it takes place very quickly.

Currently, the imaging system could take about 10 images per second, according to the researcher.

Although imaging systems that capture infrared and microwave wavelengths already exist, they are generally very expensive, bulky, or complicated to build.

In contrast, Duke's imaging system uses a thin strip of metamaterial combined with some electronics and processing software. And while he hasn't worked with visible wavelengths of light yet, Hunt notes that it could lead to a number of cheap, small, and portable sensors that could play an important role in many different fields.

Source: BBC Technology

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